1. Field of the Invention
The present invention relates to methods, apparatuses, and programs for processing an input handwritten signature in order to determine whether or not the signature is written by an authentic user, and to storage media therefor.
2. Description of the Related Art
In general, a conventional user authentication method is performed using a user ID and a password. However, users tend to forget their passwords. In such cases, it is necessary to obtain the password based on the user ID in one way or another, and a security hole results. In order not to forget his/her password, the user often uses a word which is easy to remember, e.g., the user's birthday or the name of the user's child, as the password. The use of an easy-to-remember word as the password, itself is a security hole.
In order to prevent these problems, as described in “Method and Apparatus for Authenticating a Handwritten Character String” disclosed in Japanese Patent Laid-Open No. 10-143668 and in Japanese Patent Laid-Open No. 10-171926, a user authentication method (signature authentication method) is proposed in which handwritten data (signature data) is used in place of a password.
Unlike a password, handwritten data includes the characteristics of a person even when another person inputs the same word. As a result, a person other than the authorized user will fail in user authentication. Such characteristics include the shape of the characters, the stroke order of the characters, writing speed, writing rhythm, and the like.
Unlike fingerprints, the degree of freedom in registration contents is high. By registering a word such as a spell, it becomes more difficult for a person other than the user to pose as a registered user. By registering invariable signature data, the user who has registered the signature data can easily be authenticated.
In conventional authentication methods using passwords, it is possible to hide the input password using a symbol such as “*” in order to hide the password from another person who may be able to see the screen. However, in conventional authentication methods using signatures, signature data input by a user is displayed without any alteration while it is being input, and hence, another person can easily discern the input signature. In order to prevent this problem, handwritten information can be hidden from the user while it is being input. If this is done, however, it becomes difficult for the user to input the same signature data repeatedly.
In authentication methods using passwords, when a user forgets a password, a hint such as “the name of your pet” is given to the user in order to enable the user to recall the password. However, in conventional authentication methods using signatures, it is very difficult to express the shape of a user's signature in a sentence. When the user forgets the registered signature, it is impossible to assist the user in recalling his/her signature.